Fluid-operated reciprocating pump

Abstract

A fluid-operated reciprocating pump having a central housing, a pair of chamber housings attached to opposite sides of the central housing, and a pumping diaphragm in each chamber housing that separates an inner pressure chamber from an outer pressure chamber. Each outer pressure chamber is connected to an inlet manifold and a discharge manifold, and one-way check valves control the flow of the material being pumped through the chamber. The pumping diaphragms are connected together by a connecting rod that extends through the central housing. The central housing is formed by a pair of identical, generally tubular, molded sections secured to one another in reverse relationship to define inlet and outlet ports for operating fluid, a reversing valve chamber, a pilot valve chamber, and passages connecting the reversing valve chamber to the pilot valve chamber, the inlet port and the inner pressure chambers. A reversing valve is slidably mounted in the reversing valve chamber to control the supply of operating fluid to alternate from one inner chamber to the other, and a pilot valve is slidably mounted in the pilot valve chamber to control the movement of the reversing valve. The pilot valve is controlled by a member associated with the connecting rod and located within the central housing. According to one aspect of the disclosure, the one-way check valves are neither gravity-sensitive nor otherwise sensitive to the positioning of the pump, and the inlet and discharge manifolds are located adjacent one another so that the pump may be oriented with the check valves above the outer pressure chamber (such as where the material being pumped has air or other gas entrained therein) or with the check valves below the outer pressure chambers (such as where the material being pumped has solids entrained therein).

What is claimed is: 
     
       1. A fluid-operated pump comprising: a central housing;   a pair of chamber housings each disposed at an opposite side of said central housing;   a pair of pumping members one in each of said chamber housings and dividing the interior of said chamber housings into inner and outer pressure chambers;   inlet and discharge manifolds disposed to communicate with said outer pressure chambers and having one-way check valves therein and secondary inlet and outlet ports, respectively;   connecting rod means connecting said pumping members together for common reciprocatory movement in their respective chamber housings;   said central housing comprising a pair of identical molded housing sections each having a planar joining surface whereby said sections are joined to one another in reverse relationship with the respective planar surfaces mated with one another in a central plane perpendicular to the axis of said connecting rod means to define inlet and outlet ports and passage means connecting said inlet and outlet ports to said inner chambers, said passage means including a reversing valve chamber and a pilot valve chamber, said inlet port being adapted for connection to a source of fluid under pressure;   a reversing valve movably mounted in said reversing valve chamber for controlling the supply of said fluid under pressure to alternate from one inner chamber to another;   a pilot valve movably mounted in said pilot valve chamber for controlling the movement of said reversing valve, said pilot valve comprising an elongated member adapted for reciprocating linear movement in a direction perpendicular to the direction of movement of said connecting rod means;   the axes of said reversing valve and said pilot valve being in said central plane perpendicular to the axis of said connecting rod and centered between said chamber housings; and   a pilot valve operating member secured to said connecting rod means and having radially extending bifurcations with a camming surface therein adapted to alternately engage said elongated member of said pilot valve to shift said valve between its operating positions in response to reciprocating movement of said pumping members.   
     
     
       2. A fluid-operated pump as defined in claim 1, wherein the direction of reciprocating movement of said connecting rod means is essentially in a horizontal plane. 
     
     
       3. A fluid-operated pump as defined in claim 1, wherein said outer pressure chambers each define an inlet passage communicating with said inlet manifold and an outlet passage communicating with said outlet manifold, said passages being adjacent one another and extending outwardly from their respective outer pressure chamber in a generally vertical direction away from said horizontal plane. 
     
     
       4. A fluid-operated pump as defined in claim 3, wherein said pump is adapted to be placed selectively in a first position wherein said outer chamber inlet and outlet passages extend upwardly and in a second position wherein said outer chamber inlet and outlet ports extend downwardly. 
     
     
       5. A fluid-operated pump as defined in claim 1, wherein said pilot valve operating member has a central hub positioned on said connecting rod and secured against axial movement relative thereto and means slidably keying said hub to said central housing to accommodate reciprocating movement of said connecting rod and to prevent rotary movement of said hub relative to said central housing. 
     
     
       6. A fluid-operated pump as defined in claim 5, wherein said keying means includes a key extending radially from said hub and means forming a slot in said central housing adapted to slidably receive said key. 
     
     
       7. In a fluid-operated pump including: a central housing,   a pair of chamber housings each disposed at an opposite side of said central housing,   a pair of pumping members, one in each of said chamber housings and dividing the interior of said chamber housings into inner and outer pressure chambers,   means defining inlet and discharge manifolds communicating with said outer pressure chambers, said means including one-way check valves, and   connecting rod means connecting said pumping members together for common reciprocating movement in their respective chambers;   the improvement wherein said central housing comprises a pair of identical molded housing sections joined to one another in a central plane perpendicular to the axis of said connecting rod means and in reverse relationship to define inlet and outlet ports and passage means connecting said inlet and outlet ports to said inner chambers, said passage means including a reversing valve chamber and a pilot valve chamber,   a reversing valve movably mounted in said reversing valve chamber for controlling the supply of fluid under pressure alternately to said chambers,   a pilot valve movably mounted in said pilot valve chamber for controlling the movement of said reversing valve,   the axes of said reversing valve and said pilot valve being parallel to one another and in said central plane perpendicular to said connecting rod means, and   means centrally mounted on said connecting rod for shifting said pilot valve.   
     
     
       8. A fluid-operated pump as defined in claim 7, wherein the reciprocating movement of said connecting rod means is essentially in a horizontal plane. 
     
     
       9. A fluid-operated pump as defined in claim 7, wherein said molded housing sections comprise a moldable engineeering grade plastic.